About Metal Spinning and Metal Spinning Services Including: Aluminum Spinning, CNC Metal Spinning, Copper Spinning, Flow Forming, Hydroforming, Metal Spinners, Shear Spinning, Sheet Metal Spinning, Spin Forming, Stainless Steel Spinning, Tank Heads & Titanium Spinning.
Metal spinning, often called
spin forming, is a cold worked metal fabrication technique that uses a flat round disc of sheet metal which rotates on a spinning lathe. A
metal spinner applies pressure to the rotating blank using several tools to shape the metal over a form called a mandrel. This pressure can be applied by a single tool or by multiple levers. The finished product should have no wrinkling or warble due to the high speed of rotation around the mandrel. The process is quick and cost efficient. An average metal piece will only take from 5 to 10 minutes, and to change the spinning shape, one must only replace the mandrel. This process uses sheets of various kinds of metals, including
aluminum,
titanium,
stainless steel and
copper, which are in performed shapes or go through
sheet metal spinning to become products used in the aerospace, food processing, filtration, medical, military, pharmaceutical and pulp and paper industries. Engine parts, nozzles,
tank heads, funnels, freezers, mixing bowls, filter housings, pressure vessels, cartridges and cyclones are all produced by a form of metal spinning. Metal spinning can be done by hand, but a
CNC metal spinning machine, or computer numeric controlled machine, usually produces metal spun products.
Flow forming is a popular alternative of spin forming, an advanced process that allows variation in wall thickness of the product. Tube spinning, which produces cylinder shapes, and
shear spinning, which produces cone or contoured shapes, are the 2 forms of flow forming. To obtain products with uniform thickness,
hydroforming is a type of metal spinning that uses fluid pressure to form metal into a shape.
Metal spinning is a cost-effective choice for forming metal, usually used for smaller runs. But when spinning can't meet more complex design specifications, flow forming is often used. It's the main alternative to standard metal spinning, and flow forming produces hollow, symmetrical shapes by using rollers to extrude a cross-sectional area of wall thickness of a pre-formed metal part, often called a blank or perform. The thickness of the part is determined by the gap that is maintained between the mandrel and the rollers. This gap may change, to produce a product with inconsistent or uniform wall thickness. The end product parts are round in cross section, but may be straight sided cones or contoured shapes. The metal which is worked into a shape is either preformed by welding or in sheet form. Heat resistant steels such as stainless steel are good materials for the flow forming process, because their ductility and tensile strength are ideal for cold extrusion. Flow forming is able to create seamless, single pieces that have a wide range of design flexibility with increased tensile strength.
Tube forming, a flow forming method, takes tubular performs and cold works them via rollers and a mandrel to produce a tube with uniform or variable wall thickness. When shapes are made with one closed end (like a vessel), the bottom of the perform rests against the face of the mandrel while the material is moved in the same direction as the rollers. This is called forward flow forming. Reverse flow forming is a technique that produces a part with two open ends (like a tube). The force applied by rollers pushes against a serrated ring at the end of the mandrel, which compresses and extrudes the material. Shear spinning, the second method of flow forming, produces cone-shaped metal products by a flat blank that is sheared by rollers over a rotating mandrel. The diameter of the blank doesn't change, but the thickness decreases depending on the angle of the mandrel. No material is lost in this process. Hydroforming is an alternative to standard metal spinning and flow forming. In this cost-effective process, the metal flows around a punch instead of being stretched with dyes by using high pressure hydraulic system to create parts with more consistent thickness. There are 4 types of hydroforming. The most common type, tube hydroforming, is generally performed at low pressure and produces tubular parts with high integrity and structural performance. Panel hydroforming is a high pressure process that manufactures products for the automotive and aerospace industry. The third type, low pressure hydroforming, involves reshaping tubes when the cross-section definition is not strict. High pressure hydroforming also reshapes the tube more severely than any other form. In this type of hydroforming, the length-to-circumference ratio can change up to 50 percent.
When using metal spinning to fabricate a product, it is important to note the supplier's output capability. Some metal spinning manufacturers are not capable of short run orders and may have limitations as to the diameter and thickness of final product desired. However, many suppliers offer sizes from a fraction of an inch to over 6 feet in diameter. Sometimes, a metal spinning manufacturer will only have the capacity to spin a certain type of metal, such as stainless steel or aluminum. Though not all manufacturers can offer every type of spinning service, metal spinning can mean lower tooling costs because spinner dies are simpler and cheaper. Spinning tooling can also be made in-house by many spinning shops, meaning shorter lead times. The spinning process often work-hardens the metal product as it is being shaped, providing a stronger end product. The metal spinning business continues to grow as the process becomes better through technological advances.
Types of Metal Spinning
- fabricates metal parts by rotating aluminum sheet metal on a spinning lathe.
- (computer
numerical controlled)
and related technology are most often
used during the metal spinning process. Today's modern CNC technology
has made it possible to produce high volume, close tolerance, concentric
metal parts quickly and economically. CNC machine spinners are also
used for the fabrication of other sheet
metal parts.
- are what the majority of metal spinning shops
use. Because of flexible rapid tooling and the short set up times associated
with the technique, the costs of metal spinning can be much lower than
other metal fabrication techniques.
- are still used by some manufacturers but are increasingly
rare. The spinning of the metal is machine controlled but the appliance
of pressure is done by hand, making for a very hard and cumbersome
process; the results sometimes lack uniformity from piece to piece.
- is a tool and die process that uses hydraulic fluid to make components, often for the automotive industry.
- rotate metal circles.
- is the most prominent type done by metal spinning shops. Most, however, are capable
of spinning a wide range of common to exotic metals, including aluminum,
brass, copper, hastelloy and titanium.
- are circular, pressed ends to cylindrical tanks.
- is a way to create light yet strong spun products that are resistant to corrosion and offer a lustrous appearance.
Metal Spinning Terms
- A
substance that has metallic properties and is composed of two or more
chemical elements of which at least one is an elemental metal.
- An uncontrolled deformation
pattern perpendicular to the surface of a sheet caused by compressive
stresses.
- Computer Numeric Controlled.
- The sheering tendency
of sheet metal material which occurs via the bending of the same plane.
- The reforming
of metal usually, but not necessarily, conducted at room temperature.
Also referred to as cold forming or cold forging. Contrast with hot working.
- Having the same
center, as concentric circles; having the same axis, as concentric cylinders.
- The drawing of
deeply recessed parts from sheet material through plastic flow of the
material when, the depth of the recess equals or exceeds the minimum part
width.
- A tool, usually containing
a cavity, that imparts shape to solid, molten, or powdered metal primarily
because of the shape of the tool itself.
- A circular plate
with a hole in the center contoured to fit a forming punch; used to support
the blank during the forming cycle.
- The amount of permanent
extension of the material before it fractures.
- The bending of a piece
180 usually done in two steps after a piece has been created via spinning.
First a sharp angle is created then closed via a flat punch and die.
- A device used to secure a workpiece.
- Machine tool for shaping
metal or wood; the workpiece turns about a horizontal axis against a fixed
tool.
- A tapered steel form
used to support metal as it is being formed. Also called a Chuck.
- The reduction of the
cross-sectional area of metal in a localized area by uni-axial tension
or by stretching.
- Texture of steel
that appears like an orange, either from the steel mill or after forming.
- Bending metal
a greater amount than called for in the finished piece to allow for springback.
- The realigning or adjusting
of dies or tools during a production run; not to be confused with the
operation setup that occurs before a production run.
- This is a general term
used to describe most press workings.
- Used most often
as a spacer within the spinning machine.
- The form to which
the sheet metal is formed to simulate.
Metal Spinning from Wikipedia, the free encyclopedia
Metal spinning, also known as spin forming or spinning,
is a metalworking process by which a disc or tube of metal is rotated
at high speed and formed into an axially symmetric part. Spinning can
be performed by hand or by a CNC lathe.
Metal spinning ranges from an artisan's specialty to the most advantageous
way to form round metal parts for commercial applications. Artisans
use the process to produce architectural detail, specialty lighting,
decorative household goods and urns. Commercial applications include
rocket nose cones, cookware, gas cylinders, brass instrument bells,
and public waste receptacles. Virtually any ductile metal may be formed,
from aluminum or stainless steel, to high-strength, high-temperature
alloys. The diameter and depth of formed parts are limited only by
the size of the equipment available.
Process
The spinning process is fairly simple. A mandrel, also known as a form,
is mounted in the drive section of a lathe. A pre-sized metal disk is then
clamped against the mandrel by a pressure pad, which is attached to the tailstock.
The mandrel and workpiece are then rotated together at high speeds. A localized
force is then applied to the workpiece to cause it to flow over the mandrel.
The force is usually applied via various levered tools. Simple workpieces
are just removed from the mandrel, but more complex shapes may require a
multi-piece mandrel. Extremely complex shapes can be spun over ice forms,
which then melt away after spinning. Because the final diameter of the workpiece
is always less than the starting diameter the workpiece must thicken, elongated
radially, or buckle circumferentially.
A more involved process, known as reducing or necking, allows a spun workpiece
to include reentrant geometries. If surface finish and form are not critical,
then the workpiece is "spun on air"; no mandrel is used. If the
finish or form is critical then an eccentrically mounted mandrel is used.
Tools
The basic hand metal spinning tool is called a spoon, though many other
tools (be they commercially produced, ad hoc, or improvised) can be used
to effect varied results. Spinning tools can be made of hardened steel for
using with aluminum or solid brass for spinning stainless steel or mild
steel.
Some metal spinning tools are allowed to spin on bearings during the forming
process. This reduces friction and heating of the tool, extending tool life
and improving surface finish. Rotating tools may also be coated with thin
film of ceramic to prolong tool life. Rotating tools are commonly used during
CNC metal spinning operations.
Commercially, rollers mounted on the end of levers are generally used to
form the material down to the mandrel in both hand spinning and CNC metal
spinning. Rollers vary in diameter and thickness depending on the intended use.
The wider the roller the smoother the surface of the spinning; the thinner
rollers can be used to form smaller radii.
Cutting of the metal is done by hand held cutters, often foot long
hollow bars with tool steel shaped/sharpened files attached. In CNC applications,
traditional carbide or tool steel cut-off tools are used.
The mandrel does not incur excessive forces, as found in other metalworking
processes, so it can be made from wood, plastic, or ice. For hard materials
or high volume use, the mandrel is usually made of metal.
Advantages & Disadvantages
Several operations can be performed in one set-up. Work pieces may have
re-entrant profiles and the profile in relation to the center line virtually
unrestricted.
Forming parameters and part geometry can be altered quickly, at less cost
than traditional metal forming techniques. Tooling and production costs are
also comparatively low. Spin forming is easily automated and an effective
production method for prototypes as well as high production runs.
Other methods of forming round metal parts include hydroforming, stamping
and forging or casting. Hydroforming and stamping generally have a higher
fixed cost, but a lower variable cost than metal spinning. Forging or casting
have a comparable fixed cost, but generally a higher variable cost. As machinery
for commercial applications has improved, parts are being spun with thicker
materials in excess of 1" thick steel. Conventional spinning also wastes
a considerably smaller amount of material than other methods.